Filtering material and process of making same.



' No. 66l,056. Patented Nov. 6, I900.

. m. a. A. JOLLES & J. TRENKLER.

FILTEBINC MATERIAL PROCESS OF MAKING SAI E.

A mmum flied m 97, 1599.

(No Model.)

UNITED STATES PATENT OIFFICE.

MAX JOLLES, ADOLF JOLLES, AND JULIUS TRENKLER, OF VIENNA, AUSTRIA-HUNGARY, ASSIGNORS TO FILTERWERKE KUFFLER & 00., OF SAME PLACE.

FILTERING MATERIAL AND PROCESS OF MAKING SAME.

SPECIFICATION formingpart of Letters Patent No. 661,056, dated November6, 1900.

Application filed May 27, 1899. Serial No. 718,592. (No specimens.)

To all whom it may concern. tage that in this condition they present tothe Be it known that we, MAX JOLLES, ADOLF substance to be filteredlayers that are too JOLLES, and JULIUS TRENKLER, subjects ofthick-Walled or too-finely porous, so. that filthe Emperor ofAustriaHungary, residing tration can take place only with the aid Ma atVienna, in the Province of Lower Austria, pressure or suction action.Furthermore, 55

' in the Empire of Austria-Hungary, have inthe pores of these filtersare very soon stopped vented certain new and useful Improvements up bythe impurities of the substance to be in Filters and the Process ofTheir Manufacfiltered. In consequence of its becoming ture; and we dohereby declare the following often necessary owing to this state ofthings to be a-full, clear, and exact description of the to clean andchange the stopped-up filter ele- 6o invention, such as will enableothers skilled ments, with consequent waste of time, filtrain the art towhich it appertains to make and tion by means of silicates or stoneblocks of use the same. the kind mentioned is industrially too costly Asis well known, in addition to sand, carand difficult toperform.

[5 hon, and compositions of all kinds, asbestos Now thepresent'inventiou relates to novel 65 and other porous silicates, askieselguhr and filters or novel filtering material composing sandstone,are at present mainly employed these filters, which is entirely freefrom the to form filtering substrata. Asbestos is used defectshereinbefore mentioned. in many waysviz., either directly in theReferring to the drawings, in which like form of a tissue or wovenfabric in the form parts are similarly designated, Figure l is a 70 offibers, which in order to make a filtering perspective View of a filterelement having layer are drawn by suction upon a perforated part brokenaway, and Fig. 2 a section on the support of wood or metal, or,lastly,in the form line x w of Fig. 1. of powder, which is put upon afine-mesh Over a suitable framing ct'is stretched an sieve, so as toform a layer that serves as a asbestos, wool, cotton, jute, or otheranimal, 75 filtering medium. Now if asbestos in itself vegetable, ormineral fabric b, upon which is offers a very suitable filteringmaterialneverdeposited or formed the layer of filtering matheless thefiltration'obtained with it is made terial d, hereinafter described. Thebinding almost completely illusory by its present form edge 0 unites thetwo halves of the elements of employment. Filters of asbestos tissueswhen stretched over the frame a. This fil- 8o possess, namely, thedefect that in the course tering material is produced as follows: Afineof use the meshes of the tissues become loose meshed tissue or wovenfabric is covered or thatis, they open outwhereby it is renderedimpregnated with athin layer of insoluble, possible for the smallerimpure particles of fireproof, and at the same time porous subthe liquidto be filtered to pass along in the stances, and this layer is firmlyand ins'epafiltrate, while, again, in filters of asbestos rably unitedwith the tissue before referred fibers in layers there arises thedisadvantage to by the process hereinafter described. As that thesucking on of the asbestos fibers can bestos is especially to berecommended as the never be so efiected in such a uniform manmaterialfor the fine-meshed tissue. Tissues o ner that l1IlC0\-8I6d-t. 2.,asbestos fill-interof wool, peat, linen or flax, cotton, artificial 9ostices donot remain, whichlikewise give chanwool, &c., are indeedlikewise applicable; but nels for the passage of dirt particles in thethey are less to be recommended, inasmuch as filtrate. On similargrounds the process of in consequence of the subsequently necesfilteringby means of heaped-up asbestos-powsary heating they mayunder certaincircum- 5 der also often fails. The other silicatesas stances prove tobe less durable, and this 5 kieselguhr, sandstone, clay, &c., ormixtures is especially the case when the tissue is not of the same,which are compressed into cycovered by the hereinbefore-mentionedsuper-' lindrical or prismatic shapes by various imposed layer, so as tobe perfectly uniformly known processes, and are then used as filter Idense and free from gaps, so that direct access 5o elementsexhibit ontheir side the disadvanis presented to the hot gases. By laying on Too acompletely-inc'losing layer, on the contrary, this defect is gotten ridof, since a shield is formed, as it were, which, owing to its lowheat-con ducting power, prevents the outer hot gases from exerting theirfull heat effect on the tissue beneath.

Oonformably to this invention all bodies composed for the most part ofsilicates as, for example, asbestos and m eerschanm-dust, talc,soapstone, steatite, kieselguhr, sand, pumice-stone, feldspar, quartz,silicates of alumina, also the so-called Paulke bleaching-clay andterra-cheramaterials which (see Pharmaccutische Oentralha lle, Vol. 39,pages 307 and 734) consist of alumina and niagnesiasilicates.Furthermore, bone-black or other porous kinds of carbon can be used asinsoluble, fireproof, and porous materials and either separately or inany desired mixture and in finely-powdered condition for the productionof the superincumbent layer upon the fine-meshed tissue.

The durable, firm, and inseparable or insoluble union of theabove-mentioned substances with the tissue is brought about either bymeans of silicic acid separated from alkaline silicates by treatmentwith acids and rendered insoluble by subsequent heating or by means ofequally-insoluble compounds (fiuorids) obtained by heating fromsilicofluorids which are soluble in water or dilute acids. It is ofgreat importance in connection with this that the formation of theseinsoluble compounds, acting, as it were, as cement, should take placedirectly on the tissue itself.

The combination of the porous materials before mentioned with the tissueis effected as follows: The said porous materials are made into auniform thick pap, pulp, or semifiuid by mixing them with an aqueoussolution of one or more alkaline silicates or with a solution ofsilico-fluorids (of any desired and known kind) in water or dilute acidswhich have the peculiarity of leaving behind after evaporation of thesolvent, as well as after the heating of the residue, compounds (silicicacid or fluorids) insoluble in water and acids, and this pap, pulp, orsemifiuid is laid on the tissue in a thin sheet. The coated tissue isthen as soon as it has been air-dried exposed to a great heat. Whenalkaline silicates are used, a thorough soaking of the superiucumbentlayer with dilute acids for the purpose of separating the silicic acidinust first of all take place, and the removal of the alkaline saltsthen formed is effected by subsequent lixiviation, in so far as theyhave not already been volatilized by the heating.

By means of the hereinbefore-mentioned insoluble compounds, which format a term perature of 200 to 500 Centigrade, the fireproof and poroussubstances present in the mass are cemented firmly to the tissue, aswell as to one another, as if by a binding material, and the result is athin porous layer, which, together with the asbestos tissue bei theparticular metal earth alkali.

neath, presents an excellent filtering mate rial which cannot be passedthrough even by the smallest solid particles suspended in the liquid tobe filtered. This filtering material has the further advantage over thesocalled block-filters that the thin filter layer does not affect therate of filtration too greatly, so that this nearly equals that whichcan be obtained by means of a simple tissue. If, for example, thesolution of magnesium-silico fluorid in water or dilute acids isevaporated and the residue heated, there escapes, as is well known,silicium fluor'id, and magnesium fluorid remains behind as the insolublebody MgSiFl '-'-SiFl +MgFl The hydrochloric acid that may be added tothe Water makes no difference to the result of the preceding process.Its addition is generally mainly intended to bring larger quantities ofthe silico fluorids into solution or to prevent the formation of basicsalts, and the process to be performed in its presence in the casementioned should be such that, first, by the action of the hydrochloricacid on the magnesiumsilico fluorid, hydrofluosilicic acid and magnesiumchlorid is formed, then on the subsequent heating, since thehydrolluosilicic acid splits up into silicium fiuorid and hydrofluoricacid, the magnesium chlorid is destroyed by the hydrofluoric acid formedwith the formation of magnesium fluorid and hydrochloric acid.

(1) MgSiFl -i-2HOl:MgOl +H SiFl (2) I-I,siF1,=HF1+siF1,[ (3) MgOl+2HFl:MgFl -1-2HOL It is advantageous to add to the solution of thesilico-fluorid an earth-alkali chlorid-e. g.,

calcium chlorid, strontium chlorid, -&c. whereby there is formed, afterevaporating the solvent and subsequently heating the residue to about400 centigrade, with escape of silicium fiuorid and hydrochloric acid, a

compound likewise insoluble and surpassing the magnesium fluorid inbinding power, which consists principally of the fluor salt of Thesoluble bodies existing in this residue, which originate partly in thecourse of the process (magnesium chlorid) and partly arise from theaddition in excess of the earth-alkali chlorid, may be removed bysubsequent lixiviation of the filtering material.

The hereinbefore-described process may be represented by the followingequations:

(1). MgSiFI -FOaOI -I-QHCl:

MgCl +CaOl +H SiFl (2) H S'1Fl SiFl,-{2I-IFL (3) MgCl +CaCl +tI-IFl::

MgFl +OaFl +HOL It may be remarked here that a permanently-firmcementing of the filtering mate rial is only successfully attained whenthe method characteristic of the present process of obtaining themagnesium fluorid, &;c., which acts as binding material, is carriedoutthat is to say, when the separation of the same takes place directlyon the tissue itself by heating suitable compounds, While a durablefastening of the filtering material can in no way be arrived at byplacing prepared magnesium fluorid straightway on the tissue.

For the purpose of manufacturing the novel filter which is here inquestion a frame (provided with an outlet-cock) of any desired knownkind, of wood or metal for single elements, preferably of hexagonal orcylindrical shape, for several interconnected filter elements ofprismatic (parallelepipedon) or cubical shape, is surrounded on allsides by a fine-meshed asbestos tissue,on which is placed a thin layerof a material which is produced in the following manner: One or more ofthe hereinbefore-mentioned fireproof and porous substances for example,asbestos-powder, Paulke bleaching-clay, bone-black, or a desired mixtureof such substances-is stirred into a hydrochloric-acid solution ofmagnesium silico-fluorid and calcium chlorid, the density of which isabout to Baum, until a uniform paste results. This paste is smeared overthe asbestos tissue. Afterthis is completely smeared over one waitsuntil it is air-dried and then puts the frame for from one to two hoursin an oven heated to a temperature of about 200 to 500 centigrade. Theelement taken out of the oven is cooled and washeduntil none of thesubstances-for example, calcium chlorid--adhering to' the filter arefound in the wash-Water in soluble form. The filter element is thenplaced in a vessel of sheet-iron or other suitable material and itsdischarge-pipe is joined tight with the suitably-provided outlet of thevessel.

In the case of filters of larger size several elements are placed inthis way in a large vessel of sheet-iron or cement, and their outletsare united to a common discharge-pipe of the vessel. Filtration goes onsufficiently of itself by reason of thddifference in level of the dirtywater and the filtrate; but the rate of filtration can be increased bylengthening the discharge-pipe or by using pressure or by elevating thedirty-water vessel, the filter vessel being of course necessarily closedon all sides and made of correspondingly-strong material.

For producing the firm connection between the tissue and thesuperimposed layer an aqueous solution of water-glass may be usedinstead of a solution of silico-fiuorids.

We claim- 1. The process of producing filtering media, which consists insaturating an asbestos fabric with a solution of silicic acid or asilicate and a fluorid of the alkaline earths, and render ing thecoating insoluble and adherent to said fabric by means of heat,substantially as described.

2. Theprocess ofproducingfiltering media, which consists in saturating afabric with a solution of silicic fluorids, and depositing thenon-vaporizable residues on the fabric by means of heat, substantiallyas described.

3. The process of producing filtering media, which consists in coating afabric with a solution of silicic acid or a soluble silicate,decomposing the silicic acid or the soluble silicate on the fabric bymeans of heat and coating the prepared fabric with a paste of solubleand insoluble silicates in acid solution, drying and heating,substantially as described.

4. The process of producing filtering media, which consists in coatingan asbestos fabric with a mixture of soluble or insoluble silicates andcarbon in acid solution, heating to drive 0d the vaporizableconstituents, and washing to dissolve the soluble constituents,substantially as described.

5. The process of producing filtering media, which consists in coating afabric with an acid solution of silico-fiuorids, adding thereto afluorid of the alkaline-earth metals, vap0- rizing the volatileconstituents and washing out the soluble constituents remaining afterthe heating, substantially as described.

6. The process of producing filtering media,

which consists in coating an asbestos fabric with a paste com posed of ahydrochloric-acid solution of a silico-fluorid, a fluorid of thealkaline earth metals and carbon, heating the coated fabricv to renderthe soluble constituents insolubleand vaporize the volatile fluorids,and washing to remove theremaining soluble constituents, substantiallyas described.

7. The process of producing filtering media, which consists insaturating a mineral, animal or vegetable fabric with an aqueoussolution of an alkaline silicate, and heating to a temperature of from200 to 500 centigrade, substantially as set forth.

8. The process of producing filtering media, which consists insaturating a fabric with a solution of an alkaline silicate, coating theso-prepared fabric with porous material saturated with analkaline-silicate and fluorid solution, and heating to the fusion-pointof the alkaline silicate, substantially as set forth.

9. The herein-described product, comprising a fabric havingchemically-deposited filtering media thereon, composed of insolublesilicates and fluorids.

10. The herein-described product, comprising a silicious fabric havingdeposited thereon a filtering media composed of carbon cemented bysilicates and fluorids rendered insoluble.

In testimony that we claim the foregoing as our invention we have signedour names in I presence of two subscribing Witnesses.

Witnesses:

ALVESTO S. HOGUE, AUGUST FUGGER.

